JPH03107635A - Cushion device of hydraulic bumper - Google Patents

Abstract

PURPOSE:To improve workability without requiring too much working accuracy of an oil hole rod and a valve body by standing the oil hole rod having a tapered surface on its outer circumference on the upper part of a damper cylinder and by providing the valve body which fits the outer circumference of the oil hole rod on the upper part of the inner circumference of a spacer in a free and vertically moving manner. CONSTITUTION:An inner tube which is a wheel side tube 2 is slidably inserted into an outer tube which is a car body side tube 1, a damper cylinder 3 is stood from the lower part in the wheel side tube 2, and a piston rod 7 is inserted in the damper cylinder 3 through a piston in a free and vertically moving manner. A suspension spring 9 is provided between the wheel side tube 2 and the damper cylinder 3 along the axial direction, a hollow spacer 10 is provided between the suspension spring 9 and a cap member 8 in series, and the suspension spring 9 applies force all the time to the car body side tube 1 and the piston rod 7 in the extension direction through the spacer 10 and the cap member 8. A hollow oil hole rod 13 is stood at the upper end part of the damper cylinder 3, and a tapered surface 14 is formed on the outer circumference of this oil hole rod.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a cushion for a hydraulic shock absorber suitable for use in a front fork, etc., which is interposed between the body and axle of a motorcycle or the like to damp vibrations from the road surface. Regarding equipment.

[Conventional technology]

As this type of hydraulic shock absorber, the applicant has developed, for example, the type shown in Figure 2.

The wheel side tube 2 is fitted into the vehicle body side tube 1 so as to be vertically slidable, the damper cylinder 3 stands up from below inside the wheel side tube, and the piston rod 7 is inserted into the damper cylinder 3 via a piston. is inserted so as to be vertically movable, and the piston rod 7 is connected to the vehicle body side tube l at the upper part.

A hollow oil lock case 4 is erected above the damper cylinder 3, and an oil lock piece 6 facing the oil lock case 4 is provided above the piston rod 7.

A suspension spring is interposed between the oil lock case 4 and the upper part of the vehicle body side tube 1 to constantly urge the vehicle body side tube 1 in the direction of extension.

At the time of compression, the piston rod 7 descends and gradually fits into the oil lock case 4, causing oil to flow upward from between the two, and the flow resistance acts as a cushion near the time of maximum compression.

[Problem to be solved by the invention]

In the above hydraulic shock absorber, the damper cylinder 3, oil lock case 4, and suspension spring 5 are arranged in series, so the overall basic length is long. However, depending on the mounting space of the vehicle, the basic length of the hydraulic shock absorber may be regulated, and in that case, the length of the oil lock case 4 must be shortened. On the contrary, the effective fitting cross-sectional area with the oil lock piece 6 becomes small, and there is a problem that the cushioning is not sufficiently effective. Therefore, in order to provide sufficient cushioning, it is necessary to improve the accuracy of the fitting portion between the oil lock case 4 and the oil lock piece 6, which makes workability difficult.

Therefore, an object of the present invention is to provide a cushioning device for a hydraulic shock absorber which can provide sufficient cushioning even if the basic length is shortened, and which does not require high machining accuracy of the cushion-generating member.

[Means to solve the problem]

In order to achieve the above objects, the present invention has a structure in which a vehicle body side tube and a wheel side tube are slidably fitted, a damper cylinder stands up in the wheel side tube, and a piston is inserted into the damper cylinder via a piston. In a hydraulic shock absorber, a rod is movably inserted and the body side tube is constantly urged in the direction of extension via a suspension spring, the suspension spring is placed outside the damper cylinder, and the upper part of the body side tube and A hollow spacer is interposed between the suspension spring, an oil hole rod having a tapered outer periphery is erected on the upper part of the damper cylinder, and a valve body (upper and lower) that fits on the outer periphery of the oil hole rod is placed on the upper inner periphery of the spacer. It is characterized by being movable.

[For production]

During compression, the valve body gradually fits into the outer periphery of the oil hole rod, and the flow resistance of the oil flowing upward from between the two creates a cushion.

When it is extended, the oil above pushes down on the valve body and flows downward from the outer periphery of the valve body.

〔Example〕

Embodiments of the present invention will be described below based on FIG.

The inner tube that spans the wheel side tube is slidably inserted into the outer tube that is the vehicle body side tube 1, and the damper cylinder 3 is raised from below in the wheel side tube 2, and the piston rod is inserted through the piston inside the damper cylinder 3. 7 is inserted so that it can move up and down, and the piston rod 7 is inserted.
The upper part of the tube 1 is connected to the vehicle body side tube 1 via an upper cap member 8.

A suspension spring 9 is interposed between the wheel side tube 2 and the damper cylinder 3 along the axial direction.

A hollow spacer lO is interposed in series between the suspension spring 9 and the cap member 8, and the suspension spring 9 is connected to the spacer 10.
The vehicle body side tube 1 and the piston rod 7 are constantly urged in the direction of extension via the cap member 8.

A spring seat 11 is provided at the bottom of the spacer lO,
Bearing 1 provided on the outer periphery of this spring seat 11
2 is in sliding contact with the inner periphery of the wheel side tube 2. Furthermore, an oil hole 19 is provided in the spacer 10 to provide an inner and outer oil chamber 20j.
21 are connected.

A hollow oil hole rod 13 is erected at the upper end of the damper cylinder 3, and a tapered surface 14 is formed on the outer periphery of the oil hole rod 13. In the embodiment, the diameter of the tapered surface 14 is expanded downward by gradually increasing the thickness of the oil hole rod 13 downward.

The upper part of the oil hole rod 13 may be straight.

A valve case 15 is connected to the upper inner periphery of the spacer 10 by caulking or the like, and an oil hole rod 13 is provided inside the valve case 15.
A cushion generating valve body IG, which also serves as a check valve, is inserted so as to be vertically movable and facing the outer periphery of the valve body.

The valve body 16 has a notch 17 at the bottom, and when the valve body 16 is raised, the valve body 16 comes into contact with the soil wall of the valve case 15 to cut off the flow of oil, and when the valve body 16 is lowered, contacts the valve seat 18 and allows oil to flow through the outer periphery of the valve body and the notch 17.

During compression operation, the spacer l works in conjunction with the car body side tube l.
O is lowered, and the valve body 6 gradually fits into the outer periphery of the oil hole rod 3 near maximum compression. At this time, oil below the oil chamber 20 flows above the oil chamber 20 through between the valve body 16 and the oil hole rod 13, and the valve body 16 is pushed up by the oil pressure at this time. Valve body 16
When the oil is inserted deeper into the oil hole rod 13, the flow path is narrowed by the tapered surface 14, and the flow resistance of this flow path generates a damping force according to the operating stroke, which acts as a cushion and prevents a sudden collision at maximum compression. prevent.

In the above case, when the piston rod cross-sectional area is A, the cross-sectional area between the oil hole rod 3 and the vehicle body side tube 2 is B, and the cross-sectional area between the piston rod 7 and the valve body 16 is C, A+ (B-( ,l
The flow rate of the X stroke is subject to throttling resistance.

Part of the oil in the oil chamber 20 flows through the oil hole 19 to the other oil chamber 21.
will be introduced in

Next, when shifting from the above state to the extension operation, the oil chamber 21
The oil flows out from the oil hole 19 into the oil chamber 2o. Although the oil hole 19 also generates throttling resistance during expansion and contraction, it may be a simple oil path.

Furthermore, when the valve body 16 is extended, it is lowered by hydraulic pressure from above, and the oil above the oil chamber 20 can flow downward into the oil chamber 2o via the outer periphery of the valve body 16 and the notch 17.

〔Effect of the invention〕

According to the present invention, since the suspension spring is provided outside the damper cylinder and the oil hole rod stands up on the top of the damper cylinder, the length of the oil hole rod is not limited to the basic length of the hydraulic shock absorber itself. .

This is because it can be molded to a sufficient length, which allows for a sufficient fitting length with the valve body depending on the stroke.

Cushioning near maximum compression should be sufficient. For this reason, machining accuracy of the oil hole rod and the valve body is not required so much, machinability is improved, and economical efficiency is also excellent.

[Brief explanation of drawings]

Figure 1 is a partially vertical front view of a hydraulic shock absorber according to an embodiment of the present invention, and Figure 2 is a partially vertical front view of a conventional hydraulic shock absorber. l...Vehicle side tube, 2...Wheel side tube, 3
・ψ・Damper cylinder, 7◆・・Piston rod, 9
...Suspension spring, 10---Spacer, 13...
・Oil hole rod, 14...Tapered surface. 16...Valve body.

Claims (1)

[Claims] The vehicle body side tube and the wheel side tube are slidably fitted, the damper cylinder stands up within the wheel side tube, the piston rod is movably inserted into the damper cylinder via the piston, and the vehicle body side tube is suspended. In a hydraulic shock absorber that is constantly biased in the direction of extension via a spring, a suspension spring is placed outside the damper cylinder, a hollow spacer is interposed between the upper part of the vehicle body side tube and the suspension spring, and the damper A hydraulic shock absorber characterized in that an oil hole rod having a tapered surface on the outer periphery is erected on the upper part of the cylinder, and a valve body that fits on the outer periphery of the oil hole rod is provided on the upper inner periphery of the spacer so as to be freely movable up and down. cushion device.